Surface engaging machines such as earth and road working machines, namely road graders, are used primarily to maintain or create a desired ground surface. Grader machines are subjected to extensive vibration, impact, and abrasive action, resulting from the scraping action between the cutting edge of the blade and the roadbed over which the machine travels.
The surface engaging machine typically employs a large generally horizontal blade to work the ground surface as needed. The large blade is generally made up of a blade mounted on the lower edge of the mold board, which sustains the principle of wear and abrasion. The mold board can further include some sort of cutting tool or cutting edge to etch the ground as the machine performs a scraping-grading type action.
As can be appreciated, such an operation subjects the mold board and the associated cutting tools to harsh treatment resulting in premature wearing and destruction of the mold board and cutting tools.
Efforts to protect the mold board from wear and alternatives to cutting tools include bolting an elongated blade member in increments across the entire lower edge of the mold board. With this construction, the blade forms a continuous working edge which engages the ground surface and protects the mold board. Worn blades are then replaced instead of the much more costly mold board.
Another alternative includes the use of the blade member along with a plurality of picks. The picks, teeth or cutting tools are generally attached to a holder or holder blade which in turn is bolted to the mold board to form a working edge for engaging the ground surface. In order to increase the useful life of the cutting tool, its working tip is often provided with a hardened insert to form the leading surface. The inserts, however, typically wear out quickly or the whole cutting tool is often lost.
Furthermore blade members are often over 14 foot long hardened steel structures that are very heavy and are susceptible to a short wear life due to their ongoing abrasive wear with the ground. Blade replacement can be time consuming particularly where the attachment bolts are bent or frozen, and relatively dangerous due to the size and weight of the blade segments with installed tools, making them very difficult to manhandle. Changing a set of segments is often a two-man operation. As such the harsh environment not only results in higher maintenance and repair costs, but also increased down time for the machine.
Thus a sectional grader system for a mold board which is sectional and allows for easy and accurate installation with removable cutting tools and may be installed safely by a single person is desirable.